1. Field of the Invention
This invention pertains to a carbonator having a water level control, and to a liquid level control for providing a delayed response to a rising liquid level.
2. The Prior Art
The prior carbonators are characterized by being of large size and volume and requiring rather high pressures for operation. The prior art typically utilizes a carbonator pressure of 80-150 PSIG. Control of quantities of water has been most easily and often accomplished by suspending the entire carbonator on a spring scale device and sensing the weight of the entirety of the carbonator vessel and water therein. This has both advantages and disadvantages. Functional advantages include external adjustability for minimum and maximum water levels, any shape of carbonator vessel may be used, and small cross-section vessels may be used. Disadvantages are external mechanisms for weighing, difficulty in cooling the carbonator and the inlet and outlet lines usually have to be flexible. A specific example of this structure is Gene A. Tracy U.S. Pat. No. 3,617,052.
Another type of carbonator has an internal water level sensor. This structure also has advantages and disadvantages. The advantages include direct contact of the level control with water, structural protection of the level control as it is enclosed within a pressure vessel, it's easier to refrigerate the carbonator, and fluid lines into and from the carbonator may be rigid as they do not need to flex. Disadvantages of the internal level control include false signaling due to turbulence and splashing of water within the carbonator, a relatively large area of cross section has been required in order to accommodate both carbonating and level sensing structures within the carbonator, and expensive logic units have been needed to interpret signals from level sensing structure. A specific example of this type of structure is R. T. Cornelius' U.S. Pat. No. 3,248,098.
These prior carbonator and the water level controls used with the carbonators have usually required rather complicated structure for controlling the level of water, due in large part to the violently turbulent nature of water within a carbonator during filling.
Specific examples of relevant prior U.S. patents include the following:
No. 2,414,607; P. H. Phillips is the most relevant known prior art. The Phillips carbonator features violent turbulation of water and carbon dioxide during filling and controls the water level with an electrode probe within the carbonator vessel. A housing within the vessel shields the probe from the violent water movement for preventing false "filled" signals.
No. 3,813,010; D. A. Hassell and J. R. McMillin is relevant because the preferred arrangement of hydraulic and pneumatic components comprising a beverage system within which the present invention is utilized, is disclosed and claimed. The carbonator and level control of this invention are not found in Hassell and McMillin.
No. 3,578,214; F. M. Iannelli has a carbonator with two chambers, and a reed switch is operatively connected to a float in one of the chambers.
No. 2,300,300; J. K. Lund has a carbonator with a float for operating a magnetically responsive switch.
Nos. 2,217,841 and 2,339,640; C. J. Holinger each have a violent carbonation chamber inside of a less violent reservoir chamber with the level control being in the less violent chamber.
Publication of relevancy include Catalog number 86-675B by Gems Sensor Division, Delaval Corporation, Farmington, Conn. 06032 and Catalog number 7600 by Compac Engineering, Inc., 100 Easy Street, Paradise, Calif. 95969. These publications are engineering manuals illustrating reed switches and magnetic floats for actuating the reed switches. The manuals illustrate and instruct in state of the art usage of these reed switch/float controls.
In the differential control of a liquid level at two different heights, specifically a relatively high maximum level and a much lower minimum level, it is current practice to provide two floats and two switches, and/or a logic relay system.
It is to simplification of a liquid level control of the differential type that our invention is directed; specifically to eliminate mechanical or electrical logic or components for multi-level control of liquids.